1. Field of the Invention
This invention relates to reclamation of ammonium perchlorate from solid rocket propellants. More specifically, the present invention relates to the treatment of reclaimed ammonium perchlorate with activated carbon to produce rounded ammonium perchlorate particles upon recrystallization while agitating the solution.
2. Technology Review
There is a considerable amount of waste propellant produced during the manufacture of solid propellant rocket motors. Sources of waste propellant include the excess propellant cast into the motor casing to compensate for shrinkage, rocket motors or masterbatches that do not meet specifications, as well as overage motors removed from service. In the past, this waste propellant has been disposed by open burning. More recently, efforts have been made to recover oxidizer, metallic fuel, and other valuable propellant ingredients.
Various processes for recovering oxidizer from waste propellant material are known in the art. A common technique involves leaching the oxidizer with a solvent such as hot. water. The oxidizer, usually ammonium perchlorate (AP), dissolves in the solvent permitting separation of insoluble ingredients. The AP is then recovered by crystallization. The reclaimed AP is then recrystallized and mechanically rounded in order to meet solid rocket propellant particle size distribution and shape requirements.
Recrystallization from merely lowering the AP solution temperature or exceeding solution saturation limits does not produce rounded particles. The required rounding is mechanically induced. It has been found that AP reclaimed and recrystallized from certain solid propellants produces atypical, rhombic-shaped particles which are inadequately rounded by the normal mechanical rounding process. Subsequent propellant evaluations with the reclaimed/recrystallized AP indicate that the atypical particle shape makes the propellant difficult to process and alters propellant mechanical and ballistic properties.
It will be appreciated that there is a need in the art for a process of reclaiming waste AP which will produce normal, rounded AP particles upon recrystallization.
Such process is disclosed and claimed herein.